/*
 * Created on 16-Dec-2005
 * Created by Paul Gardner
 * Copyright (C) Azureus Software, Inc, All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 */

package com.aelitis.azureus.plugins.extseed.impl.getright;

import java.net.URL;
import java.net.URLEncoder;
import java.util.Map;

import org.gudy.azureus2.core3.torrent.TOTorrent;
import org.gudy.azureus2.core3.torrent.TOTorrentFile;
import org.gudy.azureus2.core3.util.Debug;
import org.gudy.azureus2.plugins.peers.PeerManager;
import org.gudy.azureus2.plugins.torrent.Torrent;
import org.gudy.azureus2.pluginsimpl.local.PluginCoreUtils;
import org.gudy.azureus2.pluginsimpl.local.torrent.TorrentImpl;

import com.aelitis.azureus.core.peermanager.piecepicker.PiecePicker;
import com.aelitis.azureus.core.peermanager.piecepicker.PiecePriorityProvider;
import com.aelitis.azureus.plugins.extseed.ExternalSeedException;
import com.aelitis.azureus.plugins.extseed.ExternalSeedPlugin;
import com.aelitis.azureus.plugins.extseed.ExternalSeedReader;
import com.aelitis.azureus.plugins.extseed.impl.ExternalSeedReaderImpl;
import com.aelitis.azureus.plugins.extseed.impl.ExternalSeedReaderRequest;
import com.aelitis.azureus.plugins.extseed.util.ExternalSeedHTTPDownloader;
import com.aelitis.azureus.plugins.extseed.util.ExternalSeedHTTPDownloaderLinear;
import com.aelitis.azureus.plugins.extseed.util.ExternalSeedHTTPDownloaderListener;
import com.aelitis.azureus.plugins.extseed.util.ExternalSeedHTTPDownloaderRange;

public class ExternalSeedReaderGetRight extends ExternalSeedReaderImpl implements PiecePriorityProvider {
    private static final int TARGET_REQUEST_SIZE_DEFAULT = 256 * 1024;

    private URL url;
    private int port;

    private ExternalSeedHTTPDownloader[] http_downloaders;
    private long[] downloader_offsets;
    private long[] downloader_lengths;

    private int piece_size;
    private int piece_group_size;

    private long[] piece_priorities;

    private boolean linear_download;

    protected ExternalSeedReaderGetRight(ExternalSeedPlugin _plugin, Torrent _torrent, URL _url, Map _params)

    throws Exception {
        super(_plugin, _torrent, _url.getHost(), _params);

        int target_request_size = getIntParam(_params, "req_size", TARGET_REQUEST_SIZE_DEFAULT);

        linear_download = getBooleanParam(_params, "linear", false);

        url = _url;

        port = url.getPort();

        if (port == -1) {

            port = url.getDefaultPort();
        }

        piece_size = (int) getTorrent().getPieceSize();

        piece_group_size = target_request_size / piece_size;

        if (piece_group_size == 0) {

            piece_group_size = 1;
        }

        // delay the construction of the downloaders until needed
    }

    private void setupDownloaders() {
        synchronized (this) {

            if (http_downloaders != null) {

                return;
            }

            TOTorrent to_torrent = ((TorrentImpl) getTorrent()).getTorrent();

            String ua = getUserAgent();

            if (to_torrent.isSimpleTorrent()) {

                http_downloaders =
                        new ExternalSeedHTTPDownloader[] { linear_download ? new ExternalSeedHTTPDownloaderLinear(url, ua)
                                : new ExternalSeedHTTPDownloaderRange(url, ua) };

                downloader_offsets = new long[] { 0 };
                downloader_lengths = new long[] { to_torrent.getSize() };

            } else {

                TOTorrentFile[] files = to_torrent.getFiles();

                http_downloaders = new ExternalSeedHTTPDownloader[files.length];

                downloader_offsets = new long[files.length];
                downloader_lengths = new long[files.length];

                long offset = 0;

                // encoding is a problem, assume ISO-8859-1

                String base_url = url.toString();

                if (base_url.endsWith("/")) {

                    base_url = base_url.substring(0, base_url.length() - 1);
                }

                try {
                    base_url += "/" + URLEncoder.encode(new String(to_torrent.getName(), "ISO-8859-1"), "ISO-8859-1").replaceAll("\\+", "%20");

                    for (int i = 0; i < files.length; i++) {

                        TOTorrentFile file = files[i];

                        long length = file.getLength();

                        String file_url_str = base_url;

                        byte[][] bits = file.getPathComponents();

                        for (int j = 0; j < bits.length; j++) {

                            file_url_str += "/" + URLEncoder.encode(new String(bits[j], "ISO-8859-1"), "ISO-8859-1").replaceAll("\\+", "%20");
                        }

                        http_downloaders[i] =
                                linear_download ? new ExternalSeedHTTPDownloaderLinear(new URL(file_url_str), ua)
                                        : new ExternalSeedHTTPDownloaderRange(new URL(file_url_str), ua);

                        downloader_offsets[i] = offset;
                        downloader_lengths[i] = length;

                        offset += length;
                    }
                } catch (Throwable e) {

                    Debug.out(e);
                }
            }
        }
    }

    public boolean sameAs(ExternalSeedReader other) {
        if (other instanceof ExternalSeedReaderGetRight) {

            return (url.toString().equals(((ExternalSeedReaderGetRight) other).url.toString()));
        }

        return (false);
    }

    public String getName() {
        return ("HTTP Seed: " + url);
    }

    public URL getURL() {
        return (url);
    }

    public int getPort() {
        return (port);
    }

    protected int getPieceGroupSize() {
        return (piece_group_size);
    }

    protected boolean getRequestCanSpanPieces() {
        return (true);
    }

    protected void setActiveSupport(PeerManager peer_manager, boolean active) {
        if (linear_download) {

            // force overall download order to be from end of file to start (for BT peers)

            if (peer_manager != null) {

                PiecePicker picker = PluginCoreUtils.unwrap(peer_manager).getPiecePicker();

                if (active) {

                    piece_priorities = new long[peer_manager.getPieces().length];

                    for (int i = 0; i < piece_priorities.length; i++) {

                        piece_priorities[i] = 10 * 1000 + i;
                    }

                    picker.addPriorityProvider(this);

                } else {

                    piece_priorities = null;

                    picker.removePriorityProvider(this);
                }
            }

            if (!active) {

                boolean downloaders_set;

                synchronized (this) {

                    downloaders_set = http_downloaders != null;
                }

                if (downloaders_set) {

                    for (ExternalSeedHTTPDownloader d : http_downloaders) {

                        d.deactivate();
                    }
                }
            }
        }
    }

    public long[] updatePriorities(PiecePicker picker) {
        return (piece_priorities);
    }

    public void calculatePriorityOffsets(PeerManager peer_manager, int[] base_priorities) {
        if (linear_download) {

            // force us linear from front of file to end

            for (int i = 0; i < base_priorities.length; i++) {

                base_priorities[i] = TOP_PIECE_PRIORITY + base_priorities.length - (i + 1);
            }
        } else {

            super.calculatePriorityOffsets(peer_manager, base_priorities);
        }
    }

    protected void readData(ExternalSeedReaderRequest request)

    throws ExternalSeedException {
        readData(request.getStartPieceNumber(), request.getStartPieceOffset(), request.getLength(), request);
    }

    protected void readData(int start_piece_number, int start_piece_offset, int length, final ExternalSeedHTTPDownloaderListener listener)

    throws ExternalSeedException {
        setupDownloaders();

        setReconnectDelay(RECONNECT_DEFAULT, false);

        long request_start = start_piece_number * (long) piece_size + start_piece_offset;
        int request_length = length;

        if (http_downloaders.length == 1) {

            ExternalSeedHTTPDownloader http_downloader = http_downloaders[0];

            try {
                http_downloader.downloadRange(request_start, request_length, listener, isTransient());

            } catch (ExternalSeedException ese) {

                if (http_downloader.getLastResponse() == 503 && http_downloader.getLast503RetrySecs() >= 0) {

                    int retry_secs = http_downloader.getLast503RetrySecs();

                    setReconnectDelay(retry_secs * 1000, true);

                    throw (new ExternalSeedException("Server temporarily unavailable, retrying in " + retry_secs + " seconds"));

                } else {

                    throw (ese);
                }
            }
        } else {

            long request_end = request_start + request_length;

            // System.out.println( "Req: start=" + request_start + ", len=" + request_length );

            final byte[][] overlap_buffer = { null };
            final int[] overlap_buffer_position = { 0 };

            // we've got to multiplex the (possible) multiple request buffers onto (possible) multi files

            for (int i = 0; i < http_downloaders.length; i++) {

                long this_start = downloader_offsets[i];
                long this_end = this_start + downloader_lengths[i];

                if (this_end <= request_start) {

                    continue;
                }

                if (this_start >= request_end) {

                    break;
                }

                long sub_request_start = Math.max(request_start, this_start);
                long sub_request_end = Math.min(request_end, this_end);

                final int sub_len = (int) (sub_request_end - sub_request_start);

                if (sub_len == 0) {

                    continue;
                }

                ExternalSeedHTTPDownloader http_downloader = http_downloaders[i];

                // System.out.println( "    sub_req: start=" + sub_request_start + ", len=" + sub_len + ",url=" + http_downloader.getURL());

                ExternalSeedHTTPDownloaderListener sub_request = new ExternalSeedHTTPDownloaderListener() {
                    private int bytes_read;

                    private byte[] current_buffer = overlap_buffer[0];
                    private int current_buffer_position = overlap_buffer_position[0];
                    private int current_buffer_length = current_buffer == null ? -1 : Math.min(current_buffer.length, current_buffer_position
                            + sub_len);

                    public byte[] getBuffer()

                    throws ExternalSeedException {
                        if (current_buffer == null) {

                            current_buffer = listener.getBuffer();
                            current_buffer_position = 0;
                            current_buffer_length = Math.min(current_buffer.length, sub_len - bytes_read);
                        }

                        return (current_buffer);
                    }

                    public void setBufferPosition(int position) {
                        current_buffer_position = position;

                        listener.setBufferPosition(position);
                    }

                    public int getBufferPosition() {
                        return (current_buffer_position);
                    }

                    public int getBufferLength() {
                        return (current_buffer_length);
                    }

                    public int getPermittedBytes()

                    throws ExternalSeedException {
                        return (listener.getPermittedBytes());
                    }

                    public int getPermittedTime() {
                        return (listener.getPermittedTime());
                    }

                    public void reportBytesRead(int num) {
                        bytes_read += num;

                        listener.reportBytesRead(num);
                    }

                    public boolean isCancelled() {
                        return (listener.isCancelled());
                    }

                    public void done() {
                        // the current buffer is full up to the declared length

                        int rem = current_buffer.length - current_buffer_length;

                        if (bytes_read == sub_len) {

                            // this request is complete. save any partial buffer for
                            // next request

                            if (rem == 0) {

                                overlap_buffer[0] = null;
                                overlap_buffer_position[0] = 0;

                            } else {

                                overlap_buffer[0] = current_buffer;
                                overlap_buffer_position[0] = current_buffer_length;
                            }
                        }

                        // prepare for next buffer if needed

                        current_buffer = null;

                        if (rem == 0) {

                            listener.done();
                        }
                    }
                };

                try {
                    http_downloader.downloadRange(sub_request_start - this_start, sub_len, sub_request, isTransient());

                } catch (ExternalSeedException ese) {

                    if (http_downloader.getLastResponse() == 503 && http_downloader.getLast503RetrySecs() >= 0) {

                        int retry_secs = http_downloader.getLast503RetrySecs();

                        setReconnectDelay(retry_secs * 1000, true);

                        throw (new ExternalSeedException("Server temporarily unavailable, retrying in " + retry_secs + " seconds"));

                    } else {

                        throw (ese);
                    }
                }
            }
        }
    }
}
